Process for preparing a chlorinated alkene

ABSTRACT

Disclosed is a process for preparing a chlorinated alkene, comprising contacting a chlorinated alkane with a catalyst in a dehydrochlorination zone to produce a liquid reaction mixture comprising the chlorinated alkane and the chlorinated alkene, and extracting chlorinated alkene from the reaction mixture, wherein the concentration of the chlorinated alkene in the reaction mixture present in the dehydrochlorination zone is controlled such that the molar ratio of chlorinated alkene:chlorinated alkane is from 1:99 to 50:50.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Czech Patent Application No. PV2014-706, filed Oct. 16, 2014, which is hereby incorporated byreference.

The present invention relates to processes for producing high puritychlorinated alkene compounds, such as 1,1,3-trichloropropene (1240za),3,3,3-trichloropropene (1240zf), 1,1,3,3-tetrachloropropene (1230za),1,1,2,3-tetrachloropropene (1230xa), 1,1,1,2-tetrachloropropene(1230xf), 1,1,2-trichloropropene, 1,1,2,3,3-pentachloropropene,1,1,3,3,3-pentachloropropene and 1,1,2,3,3,3-hexachloropropene and alsoto compositions comprising such compounds.

Haloalkanes find utility in a range of applications. For example,halocarbons are used extensively as refrigerants, blowing agents andfoaming agents. Throughout the second half of the twentieth century, theuse of chlorofluoroalkanes increased exponentially until the 1980's,when concerns were raised about their environmental impact, specificallyregarding depletion of the ozone layer.

Subsequently, fluorinated hydrocarbons such as perfluorocarbons andhydrofluorocarbons have been used in place of chlorofluoroalkanes,although more recently, environmental concerns about the use of thatclass of compounds have been raised and legislation has been enacted inthe EU and elsewhere to reduce their use.

New classes of environmentally friendly halocarbons are emerging andhave been investigated, and in some cases, embraced in a number ofapplications, especially as refrigerants in the automotive and domesticfields. Examples of such compounds include 1,1,1,2-tetrafluoroethane(R-134a), 2-chloro-3,3,3-trifluoropropene (HFO-1233xf),1,3,3,3-tetrafluoropropene (HFO-1234ze), 3,3,3-trifluoropropene(HFO-1243zf), and 2,3,3,3-tetrafluoropropene (HFO-1234yf),1,2,3,3,3-fluoropentafluoropropene (HFO-1225ye),1-chloro-3,3,3-trifluoropropene (HFO-1233zd),3,3,4,4,4-pentafluorobutene (HFO-1345zf), 2,4,4,4-tetrafluorobut-1-ene(HFO1354mfy), 1,1,1,4,4,4-hexafluorobutene (HFO-1336mzz),3,3,4,4,5,5,5-heptafluoropentene (HFO1447fz), and1,1,1,4,4,5,5,5-octafluoropentene (HFO-1438mzz)

While these compounds are, relatively speaking, chemically non-complex,their synthesis on an industrial scale to the required levels of purityis challenging. Many synthetic routes proposed for such compoundsincreasingly use, as starting materials or intermediates, chlorinatedalkanes or alkenes. The conversion of the chlorinated alkane or alkenestarting materials to the fluorinated target compounds is usuallyachieved using hydrogen fluoride and transition metal catalysts, forexample chromium-based catalysts.

It has been recognised that when the chlorinated feedstock is obtainedfrom a multi-step process, especially if such steps are linked and runcontinuously to achieve industrially acceptable product volumes, thenthe need to prevent cumulative side reactions from generatingunacceptable impurities at each process step is very important.

The purity of the chlorinated starting materials will have a substantialeffect on the success and viability of the processes (especiallycontinuous processes) for preparing the desirable fluorinated products.The presence of certain impurities will result in side reactions,minimising the yield of the target compound. Additionally, the presenceof certain impurities will compromise catalyst life.

Chlorinated alkenes may be employed as starting materials orintermediates in processes for producing the haloalkanes discussedabove. Methods for the preparation and use of such chlorinated alkenesare provided in International Patent Application No. WO2009/085862,European Patent Application No. EP2447238, European Patent ApplicationNo. EP2646402, and US Patent Publication No US2014/0275658.

One well established method for producing chlorinated alkenes is via adehydrochlorination step in which a chlorinated alkane is converted to achlorinated alkene.

One drawback with many dehydrochlorination processes operated to date istheir reliance upon the use of alkaline hydroxide, which is notpreferable due to the environmental concerns regarding the use of suchmaterials in dehydrochlorination reactions. Further, it has been foundthat such processes are typically not economically viable.

In European Patent Application EP2687504, a process is disclosed whichseeks to avoid the use of sodium hydroxide in a dehydrochlorinationreaction. In that reaction, 1,1,1,3-tetrachloropropane isdehydrochlorinated to produce 1,1,3-trichloropropene which is thenconverted in situ to 1,1,1,2,3-pentachloropropane, preferably in theabsence of sodium hydroxide.

However, the impurity profile of 1,1,1,2,3-pentachloropropane producedin that way is unfavourable and this stems, at least partly, from theproduction of impurities during the dehydrochlorination step. In otherwords, the in situ produced 1,1,3 trichloropropene intermediate has anunacceptable impurity profile, resulting in a downstream product(1,1,1,2,3-pentachloropropane) which also has an unacceptable impurityprofile.

As can be seen from Examples 7 to 9 of that document, the obtained1,1,1,2,3-pentachloropropane included 5.8% to 8.1% oftetrachloropropene, which is not the target chlorinated alkeneintermediate in the process discussed therein, i.e. it arises as aresult of low chlorinated alkene selectivity in the dehydrochlorination.Further, factoring in the ‘heavies’ contents in those examples (3.3% to6.3%), this amounts to a loss to impurities of over 10% which isindustrially unacceptable. Further, the extraction of the impurity1,1,2,3-tetrachloropropene from 1,1,1,2,3-pentachloropropane is onerous.

In US Patent Publication No. US2014/0275658, a process is disclosedwhich employs a chloroalkane starting material necessarily containing a‘heavies’ impurity, this impurity apparently resulting in a moreselective process. The highest purity chloroalkane starting materialemployed in the processes disclosed in that application is 98.%. Thepreferred degree of conversion of chloroalkane to chloroalkene in theprocesses disclosed in US2014/0275658 is at least 60%.

There remains a need in the art for an efficient, reliable and highlyselective process for preparing chlorinated alkenes, such as1,1,3-trichloropropene, which does not additionally result in theformation of unwanted impurities, especially those which are difficultto separate from the chlorinated alkene of interest and/or which canbecome problematic in downstream processes for example, by deactivatingcatalysts employed in those processes, and/or resulting in degradationor polymerisation of the haloalkene product.

Thus, according to a first aspect of the present invention, there isprovided a process for preparing a chlorinated alkene comprisingcontacting a chlorinated alkane with a catalyst in a dehydrochlorinationzone to produce a reaction mixture comprising the chlorinated alkane andthe chlorinated alkene, and extracting the chlorinated alkene from thereaction mixture, wherein the concentration of the chlorinated alkene inthe reaction mixture present in the dehydrochlorination zone iscontrolled such that the molar ratio of chlorinated alkene:chlorinatedalkane is from 1:99 to 50:50.

It has unexpectedly been found that by controlling the level ofchlorinated alkene such that the molar ratio of that product to thechlorinated alkane starting material does not exceed 50:50advantageously prevents the formation of unwanted and problematicimpurities, such as chlorinated oligomers which can adversely affectcatalyst performance. Doing so also improves yield and catalystactivity. Advantageously, the processes of the present invention arealso highly selective.

The molar ratio of chlorinated alkene:chlorinated alkane in the reactionmixture is controlled within numerically defined limits. As thoseskilled in the art will appreciate, in such embodiments, while controlover the process is characterised herein in terms of the molar ratiobetween the chlorinated alkane starting material and the chlorinatedalkene product, it can also considered as control over the conversion ofstarting material to product—thus a molar ratio of product:startingmaterial of 20:80 equates to a conversion of 20%. The inventors havefound that limiting the conversion of the starting material as outlinedabove minimises the formation of undesirable impurities and allowsbetter catalyst lifetime. Additionally, where reference is made to amolar ratio of the product:starting material being greater than a givenvalue, this means a greater degree of conversion of the startingmaterial to product, i.e. such that the proportion of the product isincreased while the proportion of the starting material is decreased.Moreover, the inventors have surprisingly found out that the requiredmolar ratio between the chlorinated alkene product and the chlorinatedalkane starting material in the reaction mixture can be controlled notonly by significantly limiting the conversion of the starting alkanebut, advantageously, also by efficient immediate extraction of producedalkene from such reaction mixture.

In embodiments of the invention the process is continuous.

The processes of the present invention result in the formation ofchlorinated alkenes. As those skilled in the art will recognize, suchcompounds are typically highly reactive and the formation of oxygenatedorganic compounds, such as chlorinated alkanols, or chlorinated alkanoylcompounds in dehydrochlorination reactions of this type is possible. Theimportance of minimising such compounds in the products of the processesof the present invention has been recognised by the inventors of thepresent process. While the exclusion of air from the apparatus canreduce the formation of oxygenated compounds, doing so is typically moretechnically and economically demanding, especially where subatmosphericpressure environments are used.

The in situ formation of such side products can be prevented through useof processes of the present invention, and this is especiallyadvantageous in continuous processes. The reaction conditions describedherein enable the chlorinated alkene of interest to be producedselectively and be extracted from the reaction mixture, such that thereis minimised risk of the production of undesired oxygenated compounds.

Additionally or alternatively, if oxygenated compounds are formed in theprocess of the present invention, e.g. alkanols or carbonyl compounds,then these can be removed through the use of an aqueous treatment step,discussed below in more detail.

Advantageous results have also been achieved when the chlorinated alkenecontent of the reaction mixture is controlled such that the molar ratioof chlorinated alkene product:chlorinated alkane starting material inthe reaction mixture does not exceed 40:60, 30:70, 25:75, 20:80 or15:85. Additionally or alternatively, in embodiments of the invention,the molar ratio of chlorinated alkene product:chlorinated alkanestarting material in the reaction mixture may be equal to or greaterthan 2:98, 5:95 or 10:90.

Any technique or equipment may be used by those skilled in the art todetermine the composition of the reaction mixture. For example, a directdetermination of the composition can be made e.g. by providing thereaction zone with a port through which samples of the reaction mixturecan be extracted for analysis and/or taking samples of reaction mixtureupon extraction of that reaction mixture from the dehydrochlorinationzone, e.g. via a port located at or in the vicinity of the outlet of thereaction zone. Additionally or alternatively, an indirect determinationof the composition can be made e.g. by temperature control astemperature is a function of composition at constant pressure.

The level of chlorinated alkene in the reaction mixture may becontrolled in one or more of the following ways: i) by removing thechlorinated alkene from the dehydrochlorination zone (either directly,or by firstly extracting reaction mixture from the dehydrochlorinationzone and then extracting the chlorinated alkene therefrom), ii) controlof the operating conditions in the dehydrochlorination zone (e.g.temperature, pressure, agitation speed, etc) which do not favour higherlevels of chlorinated alkene formation, and/or iii) by controlling theamount of chlorinated alkane starting material and/or catalyst presentin the dehydrochlorination zone.

Chlorinated alkene may be extracted from the reaction mixture on acontinuous or batch-wise basis.

The chlorinated alkene may be extracted from the reaction mixture usingany technique known to those in the art. In embodiments, the chlorinatedalkene is extracted from the reaction mixture via distillation.Regardless of how extraction of the chlorinated alkene from the reactionmixture is carried out, the chlorinated alkene may be obtained as astream rich in the chlorinated alkene.

As used throughout this specification, the term ‘a stream rich in’ aspecific compound (or corresponding language) is used to mean that thestream comprises at least about 90%, about 95%, about 97%, about 98% orabout 99% of the specific compound. Further, the term ‘stream’ shouldnot be interpreted narrowly, but encompasses compositions (includingfractions) extracted from a mixture via any means.

For the avoidance of doubt, where reference is made to ‘continuousextraction’ of the reaction mixture in the dehydrochlorination zone orto reaction mixture from the dehydrochlorination zone, a strict literalinterpretation is not intended; one skilled in the art would recognisethat the term is used to mean that extraction occurs on a substantiallycontinuous basis, once the dehydrochlorination zone has attained thetarget operating conditions and the reaction mixture has attained asteady state.

The chlorinated alkene can be extracted directly from the reactionmixture in the dehydrochlorination zone (e.g. via direct distillation),or a portion of the reaction mixture can be firstly extracted from thedehydrochlorination zone (on a continuous or batchwise basis) and thechlorinated alkene extracted from that mixture, remotely from thedehydrochlorination zone.

In embodiments of the invention, the reaction mixture may be subjectedto additional treatment steps, for example one or more distillationsteps and/or aqueous treatment steps (discussed below in more detail).Such additional treatment steps may be carried out before and/or afterextraction of chlorinated alkene from the reaction mixture. Thoseskilled in the art will recognise that where such additional treatmentsteps are conducted post-extraction of chlorinated alkene, thechlorinated alkene content of the mixture will be lower than that in thereaction mixture formed in the dehydrochlorination zone.

In embodiments of the invention, the chlorinated alkene may be removedfrom the reaction mixture by distillation. Any technique and apparatusknown to those skilled in the art may be employed to effect extractionof the chlorinated alkene from the reaction mixture in this way. Inembodiments of the invention, a distillation column may be used, forexample a rectification column. The reaction mixture may pass or be fedinto the column bottom, with the chlorinated alkene of interest beingremoved from the top of the column as a liquid distillate.

For example, in embodiments, in which the reaction mixture is totally orpartially gaseous, for example due to the operating temperature in thedehydrochlorination zone, the apparatus may be configured such that thedehydrochlorination zone is in fluid communication with the apparatusfor conducting the distillation. In such embodiments, the distillationapparatus may be coupled to the dehydrochlorination zone. Conveniently,this enables the gaseous chlorinated alkene-containing mixture to pass(or be passed) directly from the dehydrochlorination zone in to thedistillation apparatus. Alternatively, the distillation apparatus may belocated remotely from the dehydrochlorination zone, meaning that thegaseous mixture must be extracted from the dehydrochlorination zone andpassed to the distillation apparatus.

Additionally or alternatively, where the reaction mixture is present inthe dehydrochlorination zone either partly or totally in liquid form, aportion of the liquid reaction mixture may be extracted from thedehydrochlorination zone and passed to distillation apparatus. In suchembodiments, the reaction mixture may be subjected to one or moretreatment steps (e.g. an aqueous treatment step, discussed below) whichmay precede and/or follow distillation.

In embodiments where extraction of chlorinated alkene from the reactionmixture occurs in apparatus remote from the dehydrochlorination zone,the resulting mixture, comprising unreacted chlorinated alkane startingmaterial and depleted levels of chlorinated alkene (if any) may be fedback into the dehydrochlorination zone.

In embodiments in which chlorinated alkene is extracted from thereaction mixture, at least about 30%, at least about 40%, at least about50%, at least about 60%, at least about 70%, at least about 80%, or atleast about 90% by weight of the chlorinated alkene present in thereaction mixture is extracted from that mixture.

Distillation of the chlorinated alkene from the reaction mixture can becarried out continuously, semi-continuously or batch-wise.

An advantage of the present invention is that the dehydrochlorinationreaction produces highly pure gaseous hydrogen chloride from thechlorinated alkene mixture that may be recovered using routinetechniques, for example by condensation of distillation apparatusoverhead vapours.

Thus, in embodiments of the invention in which hydrogen chloride isproduced during the dehydrochlorination reaction, the hydrogen chloridemay be extracted. This can be achieved using any equipment and/ortechniques for doing so known to those skilled in the art. For example,if the reaction mixture is subjected to distillation, the distillationapparatus may be provided with a condenser (e.g. a partial condenser),or a condenser (e.g. a partial condenser) may be provided downstream ofthe distillation apparatus, to enable the removal of hydrogen chloridegas.

Cooling apparatus (e.g. a second condenser) may additionally beemployed, e.g. downstream of the first condenser. Arranging theapparatus in this way is advantageous as the first condenser can be usedto condense the bulk of the chlorinated alkene, with the secondcondenser being used to purify the gas by condensing traces of thechlorinated alkene. The recovered chlorinated alkene is highly pure asis the hydrogen chloride.

Additionally or alternatively, an absorption column may be employed toabsorb hydrogen chloride gas to produce hydrochloric acid solution.

In embodiments of the present invention, in which hydrogen chloride gasis extracted from the dehydrochlorination zone or from reaction mixtureextracted therefrom, this may be achieved through the use of deepcooling, i.e. by extracting the gas from the reaction mixture and thencooling it to a temperature of about 0° C. or lower, about −10° C. orlower or about −20° C. or lower. The resulting condensate may berecycled back to the dehydrochlorination zone or optionally used inother associated reaction zones, e.g. hydrochlorination of glycerol.

Advantageously, hydrogen chloride extracted in these ways is highly pureand thus can be used as a reactant in upstream or downstream reactionsin the same industrial plant. An example of downstream use is for thehydrochlorination of glycerol to make monochlorohydrin ordichlorohydrin, and subsequently to lead to epichlorohydrin, glycidoland epoxies.

As mentioned above, the rate of the reaction (and thus the molar ratioof chlorinated alkane:chlorinated alkene) can be controlled bymodification of the operating temperature in the dehydrochlorinationzone. In embodiments of the invention, the dehydrochlorination reactionis carried out in the liquid phase, i.e. the reaction mixture is in theliquid form. In such embodiments, the dehydrochlorination zone may beoperated at a temperature of about 50° C., about 60° C., about 70° C.,about 80° C., about 100° C., about 120° C. or about 130° C. to about160° C., about 170° C., about 200° C., about 250° C. or about 300° C.

The reaction mixture is maintained in the dehydrochlorination zone for aperiod sufficient to enable the reaction (the conversion of chlorinatedalkane to chlorinated alkene) to proceed to the required degree ofcompletion. In embodiments of the invention, in whichdehydrochlorination occurs in the liquid phase, the residence time ofthe reaction mixture in the dehydrochlorination zone may range fromabout 0.1, about 0.2, about 0.5, about 1, about 1.5, about 2, about 2.5or about 3 to about 5 hours, about 7 hours, about 9 hours or about 10hours.

The dehydrochlorination zone may be operated at subatmospheric pressure,atmospheric pressure or superatmospheric pressure. In embodiments of theinvention, the dehydrochlorination zone is operated at atmosphericpressure or a pressure of about 10 kPa to about 400 kPa, about 40 kPa toabout 200 kPa, or about 70 kPa to about 150 kPa.

Any catalyst which increases the rate of the dehydrochlorinationreaction may be employed in the processes of the present invention. Inembodiments, the catalyst comprises a metal. In such embodiments, themetal may be present in solid form (e.g. where the catalyst is iron, itmay be present as particulate iron (e.g. iron filings or iron powder)iron mesh, iron wire, packing (structured or random), fixed bed, fluidbed, dispersions in liquid, etc. or in alloys containing iron formed inany such way, e.g. carbon steel), and/or as a salt (e.g. where thecatalyst is iron, it may be present as ferric chloride, ferrouschloride, etc). Additionally or alternatively, the apparatus in whichthe process of the present invention is conducted may be provided withcomponents formed either partially or totally of catalyst material, forexample column internals.

In embodiments of the invention in which metal is present in thereaction mixture as a salt, it may be added to the reaction mixture insalt form and/or solid metal may be added to the reaction mixture, whichthen dissolves in the reaction mixture, forming the salt in situ. Whenpresent in the form of a salt, the catalyst may be added in amorphousform, crystalline form, anhydrous form and/or in hydrated form (e.g.ferric chloride hexahydrate). Liquid form catalysts may also beemployed.

In alternative embodiments, the dehydrochlorination reaction is carriedout in the vapour phase, i.e. both the chlorinated alkane and thechlorinated alkene are in gaseous form. In such embodiments, thedehydrochlorination zone may be operated at a temperature of about 300°C. to about 500° C., about 325° to about 425° C. or about 350° C. toabout 400° C.

In embodiments of the invention in which the dehydrochlorinationreaction occurs in the vapour phase, the residence time of the reactionmixture in the dehydrochlorination zone may range from about 0.5 toabout 10 seconds.

It has been surprisingly found that, in embodiments of the invention inwhich the dehydrochlorination reaction is carried out in the vapourphase, the reaction must be properly catalysed in order to attain highyield and selectivity. Therefore, in processes of the invention, ametallic catalyst may be used, for example one containing iron at levelsof 50% by weight or greater.

Thus, according to a further aspect of the present invention, there isprovided a process for preparing a chlorinated alkene comprisingcontacting a chlorinated alkane in the vapour phase with a catalysthaving an iron content of 50% or greater in a dehydrochlorination zoneto produce a vapour-phase reaction mixture comprising the chlorinatedalkane and the chlorinated alkene.

Examples of catalysts which may be employed in processes of the presentinvention include stainless steels, for example ferritic and/or austenicsteels. Catalysts employed in processes of the present inventionpreferably have an iron content of at least about 50%, at least about60%, at least about 70%, at least about 80%, at least about 90% or atleast about 95% by weight. Pure iron may be employed as a catalyst.

Catalysts may be employed in any form, for example fluid bedarrangements and/or fixed bed arrangements. Additionally oralternatively, components of the dehydrochlorination zone comprising thecatalyst can be employed. For example, in embodiments in which thedehydrochlorination zone is in a tube reactor, the reactor tubes (or atleast the surfaces of those tubes in contact with the chlorinatedalkane) can be formed (partially or completely) of the catalyst, or beprovided with catalytic zones formed of the catalyst.

During operation of the dehydrochlorination reaction in the vapour phaseof the present invention, the catalyst may become deactivated. Thus, insuch embodiments, the processes of the present invention include acatalyst recovery step. This step can be achieved using any techniquesand/or equipment known to those skilled in the art, for example, by theinjection of an oxidant such as oxygen-rich air and/or oxygen into thedehydrochlorination zone. Prior to such a step, the flow of reactantsthrough the dehydrochlorination zone may be stopped and/or thedehydrochlorination zone may be purged (for example with nitrogen gas).If performed, once the catalyst recovery step is completed, thedehydrochlorination zone may again be purged (for example with nitrogengas) and/or the flow of reactants into the dehydrochlorination zone canbe re-started.

In embodiments in which the dehydrochlorination step is conducted in thevapour-phase, the reaction mixture extracted from thedehydrochlorination zone is typically in the vapour phase. Those hotproduct gases may be condensed using any technique and/or equipmentknown to those skilled in the art, to obtain chlorinated organiccompounds in liquid form. For example, the hot reaction mixture can becooled by indirect cooling methods, quenching (for example using spraynozzles), direct cooling methods, or the like.

Upon cooling the gases to condense the chlorinated organic compoundsfrom the reaction mixture, hydrogen chloride gas may be extracted whichcan optionally be used in upstream or downstream processes. An exampleof downstream use is for the hydrochlorination of glycerol to makemonochlorohydrin or dichlorohydrin, and subsequently to lead toepichlorohydrin and epoxies.

Regardless of whether the dehydrochlorination step occurs in the gaseousor liquid phase, the mixture of chlorinated organics, including thechlorinated alkene of interest and unreacted chlorinated alkane, as wellas impurities may then be subjected to one or more postdehydrochlorination treatment steps as discussed herein (including oneor more distillation and/or aqueous treatment steps) to obtain purechlorinated alkene, e.g. 1,1,3-trichloropropene.

Any type of reactor known to those skilled in the art may be employed inthe processes of the present invention. Specific examples of reactorsthat may be used to provide a dehydrochlorination zone are columnreactors, tubular reactors, bubble column reactors, plug/flow reactorsand continuously stirred tank reactors.

The process of the present invention may be carried out in a singledehydrochlorination zone or in a plurality of dehydrochlorination zones.Where a plurality of dehydrochlorination zones are employed, these maybe operated in sequence (i.e. such that reaction mixture is passed alonga number of dehydrochlorination zones) and/or in parallel.

In embodiments of the invention, where a plurality ofdehydrochlorination zones are employed optionally in cascade mode, thesemay be in the same or different reactors. For example, where a pluralityof (e.g. 1, 2, 3, 4, 5 or more) dehydrochlorination zones are employed,these may be provided in a plurality (e.g. 1, 2, 3, 4, 5 or more) ofreactors (e.g. continuously stirred tank reactors) which may each beoptimised to have optimised operating conditions such as temperature,residence times,

In an embodiment, a plurality of dehydrochlorination zones may bepresent in a distillation column that may be employed in processes ofthe present invention. In such embodiments, dehydrochlorination may beachieved by reactive distillation, for example where thedehydrochlorination reaction is carried out on trays in a distillationcolumn and/or on packing provided in the column. In embodiments in whichreactive distillation is carried out, the distillation column preferablycomprises a stripping zone in alkene is separated from alkane. Thestripping zone may be located below the liquid feed.

It has been found that the components of the reaction mixture (e.g.chlorinated alkene, hydrogen chloride and/or the starting material)obtainable from the dehydrochlorination reaction which is conducted inthe processes of the present invention, can unfavourably interact withcertain materials. Thus, in embodiments of the invention, those parts ofthe dehydrochlorination zone which are in contact with the reactionmixture may have an iron content of about 20% or less, about 10% or lessor about 5% or less, and/or are formed from non-metallic materials, forexample enamel, glass, impregnated graphite (e.g. impregnated withphenolic resin), silicium carbide and/or plastics materials such aspolytetrafluoroethylene, perfluoroalkoxy and/or polyvinylidene fluoride.

In embodiments of the invention, the surfaces of all equipment employedin the processes of the present invention with which chlorinated alkenewill contact are formed from suitable materials such as those identifiedabove. One possible exception is where one or more regions of thesurfaces of the apparatus employed in the processes of the presentinvention are formed of metallic material which is selected to performas a catalyst.

The inventors have also found that, under certain operating conditions,the exposure of the reactants used in the processes of the presentinvention as well as the compounds formed in those processes to sourcesof oxygen and/or moisture, including air, water vapour and/or water canlead to the formation of unwanted impurities. Thus, in embodiments ofthe present invention, dehydrochlorination and/or distillation may beconducted in an inert atmosphere, e.g. in the absence of oxygen.

The chlorinated alkane employed in the processes of the presentinvention may be fed into the dehydrochlorination zone using anytechnique known to those skilled in the art. The chlorinated alkane maybe a C₂₋₆ alkane, for example, chloroethane, chloropropane orchlorobutane. An example of a chlorinated alkane which may be employedin the processes of the present invention is 1,1,1,3-tetrachloropropane,1,1,2,2,-tetrachloropropane, 1,1,2,3-tetrachloropropane,1,2,2,3-tetrachloropropane, 1,1,1,2-tetrachloropropane,1,1,2-trichloropropane, 1,2,2-trichloropropane, 1,2,3-trichloropropane,1,1,1,2,3-pentachloropropane, 1,1,2,3,3-pentachloropropane,1,1,1,2,2-pentachloropropane, 1,1,2,2,3-pentachloropropane,1,1,1,3,3-pentachloropropane, or any chlorinated alkane having theformula: CX₃—R or CX_(a)Y_(b)—R, where a=0-3, b=0-3, X and Y are thesame or different halogen (e.g. chlorine, fluorine, bromine, iodine) andR is a substituted or unsubstituted O₂₋₅ alkyl.

The chlorinated alkane used as a starting material in the processes ofthe present invention preferably has a high degree of purity.

In embodiments of the invention, the chlorinated alkane has a puritylevel of at least about 95%, at least about 97%, at least about 98%, atleast about 98.5%, at least about 99%, or at least about 99.5%.

In embodiments, the chlorinated alkane contains less than or equal toabout 1000 ppm, less than or equal to about 500 ppm, less than or equalto 250 ppm or less than or equal to about 100 ppm of chlorinated alkaneimpurities, for example alkanes having a boiling point which is equal toor greater than the boiling point of the chlorinated alkane startingmaterial and/or the chlorinated alkene of interest and/or which, in thereaction conditions are dehydrochlorinated to produce a chlorinatedalkene impurity, for example alkenes which have a boiling point within10° C. of the alkene of interest, which have a boiling point equal to orgreater than the chlorinated alkane starting material, and/or which areisomers of the chlorinated alkene of interest.

In additional or alternative embodiments, the chlorinated alkanecontains less than or equal to about 1000 ppm, less than or equal toabout 500 ppm, less than or equal to 250 ppm or less than or equal toabout 100 ppm of chlorinated alkene impurities, for example alkeneswhich have a boiling point within 10° C. of the alkene of interest,which have a boiling point equal to or greater than the chlorinatedalkane starting material, or the chlorinated alkene compound ofinterest, and/or which are isomers of the chlorinated alkene ofinterest.

Additionally or alternatively, the chlorinated alkane comprises lessthan or equal to about 1000 ppm, less than or equal to about 500 ppm,less than or equal to about 200 ppm, less than or equal to about 100ppm, less than or equal to about 50 ppm, less than or equal to about 20ppm or less than or equal to about 10 ppm of tetrachloroethene,tetrachloropropane and/or tetrachloropentane.

Processes for producing high purity chlorinated alkane are disclosed inUK Patent Application No. 1418346.1 and Czech Patent Application No. PV2014-705, the contents of which are hereby incorporated by reference.Products of those processes advantageously comprise:

-   -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm chlorinated alkane impurities (i.e. chlorinated alkane        compounds other than the chlorinated alkane starting material),    -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm chlorinated alkene impurities (i.e. chlorinated alkene        compounds other than the chlorinated alkene target compound),    -   less than about 1000 ppm, less than about 500 ppm, less than        about 200 ppm, less than about 100 ppm, less than about 50 ppm        or less than about 20 ppm of water,    -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm oxygenated organic compounds,    -   less than about 2000 ppm, less than about 1000 ppm, less than        about 500 ppm, less than about 200 ppm or less than about 100        ppm brominated compounds, and/or    -   less than about 500 ppm, less than about 200 ppm, less than        about 100 ppm, less than about 50 ppm or less than about 20 ppm        metal.

The chlorinated alkane material used as a starting material in theprocesses of the present invention may be provided in a compositionhaving the impurity profile as outlined above.

The inventors of the process disclosed herein have found that, inembodiments of the present invention, certain impurities, such ashexachloroethane and/or higher alkanes, e.g. chloropentanes, such astetrachloropentane, e.g. 1,3,3,5-tetrachloropentane (when thechlorinated alkane starting material is 1,1,1,3-tetrachloropropane)which may be present in industrial scale supply volumes of chlorinatedalkanes (e.g. 1,1,1,3-tetrachloropropane), can severely retard thedehydrochlorination reaction process.

Thus, in such embodiments, higher purity starting haloalkanes, withreduced amounts of such higher haloalkane impurities may be preferablesuch that efficient conversion to the desired haloalkene is achieved atlower temperatures.

The chlorinated alkene produced in the processes of the invention may bea C₂₋₆ alkene, for example, chloroethene, chloropropene or chlorobutene.An example of a chlorinated alkene which may be produced in theprocesses of the invention is 1,1,3-trichloropropene (1240za),1,1,3,3-tetrachloropropene (1230za), 1,1,2,3-tetrachloropropene(1230xa), 2,2,2,3-tetrachloropropene (1230xf), 3,3,3-trichloropropene,2,3,3,3-tetrachloropropene and chlorinated alkenes having the formula:CX_(c)Y_(d)═R, where X and Y are the same or different halogen (e.g.fluorine or chlorine), c is 0 to 2, d is 0 to 2 and R is a substitutedor unsubstituted C₂₋₅ alkyl.

One of the advantages of the processes of the present invention is thatthey permit the production of a target chlorinated alkene with highisomeric selectivity. Thus, in embodiments of the invention, thechlorinated alkene product is produced with isomeric selectivity of atleast about 95%, at least about 97%, at least about 98%, at least about99%, at least about 99.5%, at least about 99.7%, at least about 99.8% orat least about 99.9%.

The feed of chlorinated alkane and/or catalyst into thedehydrochlorination zone may be continuous or intermittent, as mayextraction of the reaction mixture.

One advantage of the processes of the present invention is that desirousresults are obtained whether the dehydrochlorination zone is operated ina continuous or batch process. The terms ‘continuous process’ and ‘batchprocess’ will be understood by those skilled in the art.

A further advantage of the present invention is that it enables highpurity chlorinated alkene compounds to be produced without the use ofalkaline hydroxides. Thus, in embodiments or the present invention, noalkaline hydroxide is added to the dehydrochlorination zone and/or thereaction medium present in the dehydrochlorination zone is free ofalkaline hydroxide.

As mentioned above, in embodiments of the invention, reaction mixturecomprising chlorinated alkane, chlorinated alkene and catalyst may beextracted from the dehydrochlorination zone. This may be subjected tofurther treatment steps.

In such embodiments, such a treatment step may be an aqueous washingstep in which the extracted mixture is optionally filtered and then fedinto an aqueous treatment zone. This step may be carried out before orafter extraction of the chlorinated alkene from the mixture.

The mixture is contacted with an aqueous medium in the aqueous treatmentzone which serves to deactivate the catalyst. The mixture may becontacted with acid in the aqueous treatment zone, for example inorganicacid such as sulphuric acid, phosphoric acid and/or hydrochloric acid.The acid may be pure, or may be dilute. Where dilute acid is used, thismay provide the aqueous medium. The pH value of the aqueous mediumshould be sufficiently low to enable effective separation of thebiphasic mixture.

The aqueous treatment step has the advantageous effect of removingcertain classes of otherwise problematic impurities from the mixture,especially oxygenated impurities.

In such embodiments, catalyst deactivation can be achieved with only ashort contact time, e.g. about 5, about 10, about 20 or about 30minutes, with water at low temperature is required. For hydrolysis andextraction of chlorinated, oxygenated impurities, the contact time withthe water may be longer, e.g. up to about 1 hour, about 2 hours, about 5hours or about 10 hours and/or at a temperature of about 50° C. or less,about 40° C. or less or about 30° C. or less.

Thus, according to a further aspect, there is provided a process forremoving oxygenated organic impurities from a mixture comprising achlorinated alkene, oxygenated organic impurities and optionally acatalyst and/or a chlorinated alkane, comprising contacting the mixturewith an aqueous medium to form a biphasic mixture and extracting theorganic phase from that biphasic mixture. In embodiments of theinvention, the mixture of this aspect of the invention is or comprisesthe mixture extracted from the dehydrochlorination zone.

Where a dilute acid is employed, this may additionally provide theaqueous medium with which the mixture is contacted. Additionally, oralternatively, the aqueous medium may comprise water (in any form, e.g.including steam) which may be added separately into the aqueoustreatment zone.

In embodiments in which acid is added into the aqueous treatment zone,this preferably reduces the pH of the mixture present therein to about 6or lower, about 5 or lower, about 4 or lower, about 2 or lower or about1 or lower.

A proportion (e.g. at least about 30%, at least about 40%, at leastabout 50%, at least about 60%, at least about 70%, or at least about80%) of the unreacted alkane and/or chlorinated alkene may be extractedfrom the mixture formed in the aqueous treatment zone using anytechniques or equipment known to those skilled in the art.

For example, in embodiments in which the mixture is partly or totally ingaseous form, for example due to the operating temperature in theaqueous treatment zone and/or through the addition of steam as theaqueous medium, the gaseous mixture may be subjected to distillation. Insuch embodiments, the distillation device may be in fluid communicationwith the aqueous treatment zone (optionally coupled to that zone) or maybe remote from the aqueous treatment zone.

Additionally or alternatively, where the mixture is partly or totally inliquid form, that mixture may be extracted from the aqueous treatmentzone and subjected to distillation.

In embodiments where such a distillation step is conducted, a streamcomprising (and optionally rich in) chlorinated alkane starting materialand/or chlorinated alkene product may be obtained.

The chlorinated alkane and/or chlorinated alkene extracted from themixture fed in to the aqueous treatment zone may be recycled back to thedehydrochlorination zone for use as a starting material.

A biphasic mixture, comprising an aqueous phase and an organic phase maybe formed in the aqueous treatment zone (or in certain embodiments,remotely therefrom), as a result of the presence of both the aqueousmedium and also the predominantly organic mixture.

In such embodiments where a biphasic mixture is formed, the organicphase may be extracted from the biphasic mixture using phase separationtechniques and/or equipment known to those skilled in the art. Where thebiphasic mixture is formed in the aqueous treatment zone, the organicphase can be separated from the aqueous phase by the sequentialextraction of the phases from the aqueous treatment zone. The aqueousphase, which contains impurities removed from the mixture can be furthertreated.

To maximise phase separation efficiency and thus facilitate extractionof that phase from the biphasic mixture, a haloalkane extraction agentand/or phase separation intensifier (for example, the chlorinated alkanestarting material and/or various alcohols and/or ketones) may be addedto the aqueous treatment zone, either intermittently or continuously,using techniques and/or equipment known to those skilled in the art. Theuse of the chlorinated alkane starting material is preferred as thiscompound is part of the process and thus does not require removal usingspecific separation steps.

Optionally, phase separation intensifiers such as polar alcohols and/orketones with boiling points sufficiently different to the chlorinatedalkene and chlorinated alkane present in the reaction mixture may beemployed. The difference in boiling points should be at least 20° C., atleast about 30° C., at least about 40° C., at least about 50° C. or atleast about 60° C. Examples of phase separation intensifiers that may beemployed include aliphatic ketones e.g. acetone and aliphatic alcoholse.g. methanol, ethanol, propanol/s, butanol/s.

In embodiments of the invention, the extracted organic phase may then besubjected to a distillation step in which streams of (and optionallyrich in) the chlorinated alkene of interest and/or unreacted chlorinatedalkane are distilled off. Such a step may be performed regardless ofwhether extraction of chlorinated alkene from the reaction mixture wascarried out prior to aqueous treatment or not. The stream of unreactedchlorinated alkane may be recycled back to the dehydrochlorination zone.A heavy ends residue may be extracted from the distillation apparatus,optionally filtered and incinerated and/or subjected to high temperaturechlorinolysis.

The organic phase comprising chlorinated alkane and/or chlorinatedalkene as well as haloalkane extraction agent and/or phase separationintensifier may be fed back in to the dehydrochlorination zone. In suchembodiments, a distillation step to remove the phase separationintensifier (if used) or other components of the organic phase may beconducted.

Reducing the water content of chlorinated alkene has been found to usesuch alkene in downstream applications such as chlorination. Thus, inembodiments of present invention, process conditions are controlled suchthat the obtained chlorinated alkene product/s comprise less than about500 ppm, about 250 ppm or less, about 100 ppm or less or about 50 ppm orless of water.

As can be seen from the disclosure provided herein, the inventiveprocesses of the present invention can be operated in an integratedprocess in a fully continuous mode, optionally in combination with otherprocesses. The process steps of the present invention may employstarting compounds which are converted to highly pure intermediateswhich are themselves further processed to the required targetchlorinated compounds. Those compounds have the requisite purity to beemployed as feedstocks in a range of downstream processes, for examplehydrofluorination conversions.

The processes of the present invention enable product purity levels tobe controlled to attain highly pure target compounds. The processesadvantageously balance high yields, high selectivity and high efficiencywhich is particularly challenging, especially in continuous processes.The processes of the present invention enable high purity chlorinatedalkene compounds to be economically produced on an industrial scale,those compounds having very low levels of a range of impurities,

The processes of the present invention are particularly advantageous asthey enable highly pure chlorinated alkenes to be produced using simpleand straightforward techniques and equipment with which one skilled inthe art would be familiar.

In embodiments of the invention, the processes of the invention can beused to produce high purity chlorinated alkene compositions whichcomprise:

About 95% or more, about 97% or more, about 99% or more, about 99.2% ormore about 99.5% or more or about 99.7% or more of the chlorinatedalkene,

Less than about 50000 ppm, less than about 20000 ppm, less than about10000 ppm, less than about 5000 ppm, less than about 2000 ppm, less thanabout 1000 ppm, less than about 500 ppm, less than about 200 ppm, orless than about 100 ppm of chlorinated alkane starting material,

Less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, or less than about 100 ppm of chlorinated C₅₋₆ alkane impurities,

Less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, or less than about 100 ppm of chlorinated alkene impurities (i.e.chlorinated alkenes other than the compound of interest),

Less than about 500 ppm, less than about 200 ppm, less than about 100ppm, less than about 50 ppm, less than about 20 ppm, less than about 10ppm or less than about 5 ppm metal,

Less than about 1000 ppm, less than about 500 ppm, less than about 250ppm, or less than about 100 ppm of oxygenated organic compounds and/or

Less than about 500 ppm, about 250 ppm or less, about 100 ppm or less orabout 50 ppm or less of water.

In embodiments of the invention, stabilisers can be added to thecompositions of the present invention. Examples of stabilisers that maybe employed include hydroxylated aromatic compounds, amines, thiazines,etc. Where employed, stabilisers are typically employed in amounts ofabout 1 to about 100 ppm or about 2 to about 50 ppm. The use of suchstabilisers advantageously enables the chlorinated alkene compositionsof the present invention to be stored in oxygen-containing environments.

As mentioned previously, the prior art fails to disclose or teachprocesses for producing chlorinated alkenes having such a high degree ofpurity or high isomeric selectivity. Thus, according to further aspectsof the present invention, there are provided high purity chlorinatedalkene compositions as set out above.

The impurity profile of compositions comprising chlorinated alkenes ofthe present invention can be determined using conventional analyticalmethods including gas chromatography using a high performance capillarycolumn.

For the avoidance of doubt, where reference is made to units of pressure(kPa) it is the absolute value which is identified. Where values arepresented as percentages, they are percentages by weight unlessotherwise stated.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1—Dehydrochlorination step (1,1,1,3-tetrachloropropane conversionto 1,1,3-trichloropropene)

1 1,1,1,3-tetrachloropropane feed stream 2 ferric chloride feed stream 3continuously stirred tank reactor 4 reaction residue 5 filter 6 filtercake 7 filtrate 8 distillation column 9 1,1,3-trichloropropene richstream 10 partial condenser 11 gaseous hydrogen chloride stream 121,1,3-trichloropropene rich stream 13 reflux divider 14 reflux stream 15purified 1,1,3-trichloropropene product stream

FIG. 2—Aqueous treatment step

101 aqueous hydrochloric acid feed stream 102 residue feed stream (fromthe reactor in FIG. 1, stream 4) 103 haloalkane extraction agent feedstream 104 105 washing tank 106 washing tank outlet 107 filter 108filter cake 109 organic phase stream 110 aqueous phase stream 111distillation column 112 chlorinated alkanes stream 113 condenser 114intermediate line 115 reflux liquid-liquid separator 116 aqueous phase(reflux) stream 117 organic phase (1,1,1,3-tetrachloropropane) stream

FIG. 3—Distillation step

201 organic phase feed stream 202 distillation boiler 203 heavy endsresidue stream 204 filter 205 filter cake 206 liquid residue 207distillation column 208 distillate stream 209 condenser 210 intermediateline 211 reflux divider 212 reflux stream 213.1 1,1,3-trichloropropenefraction 213.2 1,1,1,3-tetrachloropropane fraction

EXAMPLES

Abbreviations used:

TeCPa=1,1,1,3-tetrachloropropaneTCPe=trichloropropene

Example 1 Production of 1,1,3-Trichloropropene from1,1,1,3-Tetrachloropropane

FIG. 1 shows a schematic drawing of a system which can be used tooperate processes of the present invention. 1,1,1,3-tetrachloropropaneand ferric chloride are added into the continuously stirred tank reactor3 via lines 1 and 2. The addition of ferric chloride is conducted usinga controlled feed. The continuously stirred tank reactor is operated ata temperature of 140° C. to 145° C. and at atmospheric pressure.

The 1,1,1,3-tetrachloropropane is converted to 1,1,3-trichloropropene inthe continuously stirred tank reactor 3, which fulfils the role of thedehydrochlorination zone. The residence time of the reaction mixture inthe reactor 3 is limited to prevent the excessive conversion of1,1,1,3-tetrachloropropane to 1,1,3-trichloropropene and thus, the molarratio of 1,1,3-trichloropropene:1,1,1,3-tetrachloropropane does notexceed 50:50.

A proportion of 1,1,3-trichloropropene is extracted from the reactionmixture through the use of distillation column 8. Reaction mixture isfed into the bottom of the distillation column 8 and a1,1,3-trichloropropene rich stream is withdrawn as overhead vapours vialine 9. A partial condenser 10 functions to extract gaseous hydrogenchloride from the 1,1,3-trichloropropene rich stream via line 11. The1,1,3-trichloropropene rich stream is then fed via line 12 to a refluxdivider 13, and a stream of purified 1,1,3-trichloropropene is taken offvia line 15. A proportion of the 1,1,3-trichloropropene rich stream isfed back as a reflux to distillation column 8 via line 14.

A mixture comprising catalyst, unreacted 1,1,1,3-tetrachloropropane anda limited amount of 1,1,3-trichloropropene is extracted via line 4 fromthe reactor 3 to a filter 5. The obtained filter cake is extracted vialine 6 and the filtrate is passed via line 7 for aqueous treatment, asshown in FIG. 2.

In FIG. 2, the mixture from the reactor in FIG. 1 is fed via line 102into a washing tank 105 including a stripping boiler. For better liquidphase separation efficiency, 1,1,1,3 tetrachloropropane or anotherhaloalkane extraction agent is fed into the washing tank via line 103.Aqueous hydrochloric acid is fed into the washing tank 105 via line 101.

A biphasic mixture is formed in the tank 105 and the organic phase isextracted from the tank 105 via line 106, filtered 107 and taken vialine 109 for further treatment, as shown in FIG. 3. The remainingaqueous phase is extracted via line 110 for further treatment. Thefilter cake is extracted (108)

1,1,1,3-tetrachloropropane and 1,1,3-trichloropropene dissolved in theaqueous layer present in the washing tank 105 are extracted therefrom bymeans of a steam distillation column 111. Stripped chlorinated alkanesare passed via line 112 from the distillation column 111 to a condenser113 and then via line 114 to a reflux liquid-liquid separator 115 wheretwo layers are formed. The stripped 1,1,1,3-tetrachloropropane is thentaken off as an organic phase via line 117 and an aqueous phase isrefluxed back to the distillation column via line 116.

Turning to FIG. 3, the organic phase is fed via line 201 intodistillation boiler 202. 1,1,1,3-tetrachloropropane and1,1,3-trichloropropene are extracted from the formed mixture usingdistillation column 207, condenser 209 and reflux divider 211 to producefractions of 1,1,3-trichloropropene 213.1 and 1,1,1,3-tetrachloropropane213.2. The fraction of 1,1,1,3-tetrachloropropane is recycled back tothe dehydrochlorination zone while the fraction of1,1,3-trichloropropene is stored or transported for use in downstreamreactions employing that chlorinated alkene as a starting material

A heavy ends residue is extracted from boiler 202 via line 203 andfiltered 204. The obtained filter cake and liquid residue are extractedvia lines 205 and 206 respectively and recycled or treated.

Using the apparatus and process conditions outlined above, 3563 kg of1,1,1,3-Tetrachloropropane (1113TeCPa, 99.925% purity) was continuouslyprocessed with an average hourly loading 63.1 kg/h to produce1,1,3-Trichloropropene (113TCPe). Basic parameters of disclosed processcarried out according to Example 1 are as following.

Basic parameters Reactor mean residence time (min) 174 Reactortemperature (° C.) 141 Reactor pressure (kPa) 101 Overall reaction1113TeCPa conversion (%) 91.7 Overall 113TCpe reaction yield (molTCPe/mol TeCPa 97.4 converted, in %) Overall 113TCpe yield including theall process steps 96.5 described in Example 1

The full impurity profile of the purified product of the above-describedembodiment is presented in the following table. The figures are given asa weighted average of the profiles for the product obtained in line 15in FIG. 1 and line 213.1 in FIG. 3.

Pilot plant Wt % Perchloroethylene 0.011 1,1,3-Trichloropropene 97.0932,3-dichloropropanoyl chloride 0.028 1,1,3,3-Tetrachloropropene 0.0191,1,1,3-Tetrachloropropane 2.573 unknown 0.276

As can be seen, the process of the present invention can be operated toproduce highly pure chlorinated alkene material.

Example 2 Production of 1,1,3-Trichloropropane from1,1,1,3-Tetrachloropropane

This example was conducted using the apparatus and techniques employedin Example 1 above, except where otherwise stated. The continuouslystirred tank reactor was operated at a temperature of about 149° C. andat atmospheric pressure. The molar ratio of1,1,3-trichloropropene:1,1,1,3-tetrachloropropane in the reactor wascontrolled such that it did not exceed 30:70. Using the apparatus andprocess conditions outlined above, 1543.8 kg of1,1,1,3-Tetrachloropropane (1113TeCPa, 99.901% purity) was continuouslyprocessed with an average hourly loading 47.5 kg/h to produce1,1,3-Trichloropropene (113TCPe). Catalyst was added in the form ofFeCl₃ aqueous solution to provide a catalyst content of 66 ppm, based onfeedstock 1113TeCPa. Basic parameters of disclosed process carried outaccording to Example 1 are as following.

Basic parameters Reactor mean residence time (min) 287 Reactortemperature (° C.) 149 Reactor pressure (kPa) 101 Overall reaction1113TeCPa conversion (%) 91.4 Overall 113TCPe reaction yield (molTCPe/mol 98.7 TeCPa converted, in %) Overall 113TCPe yield in %including the all 97.8 process steps described in Example

The full impurity profile of the product of the above-describedembodiment is presented in the following table. The figures are given asa weighted average of the profiles for the product obtained in line 15in FIG. 1 and line 213.1 in FIG. 3.

Compound Wt % Perchloropethylene 0.006 3,3,3-Tetrachlororpropene 0.0381,1,3-Tetrachloropropene 99.347 2,3-dichloropropanoyl chloride 0.0451,1,3,3-Tetrachloropropene 0.004 1,1,1,3-Tetrachloropropane 0.322unknown 0.238

As can be seen, when the dehydrochlorination reaction is controlled suchthat the molar ratio of1,1,3-trichloropropene:1,1,1,3-tetrachloropropane does not exceed 30:70,the process of the present invention can be operated to produce highlypure chlorinated alkene material with the very high selectivity and inhigh yield. Of note is that 3,3,3-Tetrachlororpropene is only formed intrace amounts. This is particularly advantageous as3,3,3-Tetrachloropropene is a very reactive olefin contaminant with afree induced (activated) double bond and can be a precursor of highlyproblematic oxygenated impurities.

Example 3 Alkene:Alkane Ratio in Reaction Mixture

These examples were conducted using the apparatus and techniquesemployed in Example 1 above, except where otherwise stated. In each ofthese trials, the reaction progress was controlled such that there was adifferent ratio between1,1,3-Trichloropropene:1,1,1,3-Tetrachloropropane in the reactionmixture present in the reactor (equip. 3) reaction mixture (stream 7) ineach trial. The amount of dosed catalyst FeCl3 was controlled tomaintain the reaction conversion rate at about 90%. The influence ofdifferent levels of 113TCPe in reaction mixture on the heavy oligomersformation and catalyst deactivation is shown in the following tables:

Heavy Oligomer Formation 3-1 3-2 3-3 3-4 3-5 3-6 Calculated 23:77 22:7834:66 43:57 46:54 43:57 TCPe:TeCPa molar ratio in reac. mix TCPe (%) in18.95 18.25 27.6 34.54 32.01 34.31 reaction mixture Heavy 0.36% 0.40%1.05% 1.57% 2.87% 2.54% oligomers/TCPe 3-7 3-8 3-9 3-10 3-11 3-12Calculated 39:61 37:63 40:60 39:61 38:62 39:31 TCPe:TeCPa molar ratio inreac. mix TCPe (%) in 32.1 29.94 32.84 31.46 30.56 31.83 reactionmixture Heavy 1.56% 1.79% 1.65% 1.01% 1.47% 1.55% oligomers/TCPe

Catalyst Deactivation 3-1 3-2 3-3 3-4 3-5 3-6 TCPe (%) in 18.95 22.3627.6 34.54 32.01 34.313-1 reaction mixture Calculated 23:77 22:78 34:6643:57 46:54 43:57 TCPe:TeCPa molar ratio in reac. mix Required 26.5 26.566 101 116 78 conc. of FeCl3 in feedstock 3-7 3-8 3-9 3-10 3-11 3-12TCPe (%) in 32.1 29.94 32.84 31.46 30.56 31.83 reaction mixtureCalculated 39:61 37:63 40:60 39:61 38:62 39:61 TCPe:TeCPa molar ratio inreac. mix Required 132 132 105 177 106 74 conc. of FeCl3 in feedstock

As can be seen from this example, when the specific apparatus andtechniques employed, an increase in the molar ratio of the product tothe starting material (increased amount of the product in the reactionmixture) corresponds to an increase in the formation of heavy oligomers.Further, if the 1,1,3-Trichloropropene concentration is high, catalystdeactivation was also observed.

Example 4 Compatibility of the Product Fluid with Various Materials

An Erlenmeyer glass flask was filled with pure distilled1,1,3-Trichloropropene with purity of >99%. The test constructionmaterial sample was immersed in the liquid and the system was closedwith a plastic plug.

Samples of the Trichloropropene were regularly taken from the flask. Theconstruction material samples were weighed before and after trail. Thetemperature of the liquid was ambient laboratory conditions, around 25°C.

The major changes in the quality of the Trichloropropene are shown inthe following table, as a % change in purity:

Feedstock 4-1 4-2 4-3 4-4 Trial duration 0 day 29 days 29 days 30 days30 days Construction CS SS 1.4541 Ti C-276 Material 1,1,3-Trichloropro-0 −53.75 −3.70 −3.27 −0.67 pene - relative change (%) Sum of oligomers 042.68 0.20 0.32 0.01 (%)

CS=carbon steel, SS=stainless steel, Ti=Titanium, C-276=Hastelloy C-276

In a second set of trials, an Erlenmeyer glass flask equipped with aback cooler and oil heating bath with controlled temperature was filledwith pure distilled 1,1,3-Trichlorpropene with a purity of >99%. Thetest material sample was immersed in the liquid and the system waspartially closed using a plastic plug. Samples of Trichloropropene wereregularly taken from the flask. The material samples were weighed beforeand after trail. The temperature of the liquid was controlled at 100° C.The major changes in the liquid Trichloropropene are shown in thefollowing table:

feedstock 4-5 4-6 4-7 4-8 Trial duration 0 day 5 48 5 48 hours hourshours hours Construction Material Glass as Impregnated material graphiteof flask 1,1,3-Trichloropropene - 0 −0.32 −2.31 −0.30 −2.00 relativechange (%) Sum of oligomers (%) 0  0.05  0.28  0.05  0.34 feedstock 4-9h 4-10 4-11 4-12 Trial duration 0 5 48 5 48 hours hours hours hourshours Construction Material SS 1.4341 SS 1.4541 1,1,3-Trichloropropene -0 −0.54 −3.08 −0.51 −2.80 relative change (%) Sum of oligomers (%) 0 0.27  1.01  0.29  1.29

As can be seen from this example, the use of carbon steel appeared to bechallenging as it is not compatible with the process fluid consisting of1,1,3-Trichlorpropene. Stainless steel and titanium have also poorperformance, resulting in the formation of significant amounts ofoligomers are formed. From the tested metal materials, the Ni-alloyHastelloy C-276 has excellent results. It can be seen also that glass(or enamel) and other non-metallic material, such as phenolic resinimpregnated graphite, are also more suitable.

Example 5 Problematic Chlorinated Alkene Impurities

In many downstream reactions in which chlorinated alkenes are used asstarting materials, the presence of oxygenated organic impurities isproblematic. This example demonstrates that certain impurities have asurprising propensity to form such compounds.

A four neck glass flask equipped with a stirrer, thermometer, backcooler, feed and discharge neck and cooling bath was filled with waterand chlorine gas was bubbled into the water to produce a weak solutionof hypochlorous acid. When an appropriate amount of chlorine had beenintroduced into the water, a feedstock consisting obtained from theprocess of Example 1 comprising 1,1,3-Trichloropropene with a purity of98.9% was slowly dropped into the prepared solution of hypochlorous acidfor a period of 90 min and cooled. The pressure was atmospheric andtemperature close to 20° C. The same procedure was repeated with3,3,3-Trichlorpropene having a purity of 68.1%. After reactioncompletion the systems formed bi-phasic mixtures. The organic phase(product) was extracted and then analyzed by GC. The results are shownin the following table:

5-1 5-2 Hypochlorination of Feedstock Product Feedstock ProductTrichloropropenes (%) (%) (%) (%) 3,3,3-Trichloropropene 68.063 33.5440.024 0.023 1,1,3-Trichloropropene 21.772 16.651 98.922 91.3741,1,1,2,3-Pentachloropropane 20.942 6.800 1,1,1,3-Tetrachloropropan-2-12.792 0.018 ol

As can be seen from this example, 1,1,3-Trichlorpropene reacts withchlorine in water to produce 1,1,1,2,3-Pentachloropropane, while3,3,3-Trichloropropene reacts significantly to produce correspondingtetrachlorohydrines, especially 1,1,1,3-Tetrachloropropan-2-ol.

In other words, 1,1,3-Trichlorpropene reacts to produce a product ofcommercial interest, while 3,3,3-Trichloropropene reacts to the producean oxygenated impurity which cannot be easily removed from the1,1,1,2,3-Pentachloropropane. As is apparent from Examples 1 and 2above, the processes of the present invention can be advantageouslyemployed to produce 1,1,3-trichloropropene resulting in the formation ofonly trace amounts of 3,3,3-trichloropropene.

1. A process for preparing a chlorinated alkene comprising contacting achlorinated alkane with a catalyst in a dehydrochlorination zone toproduce a liquid reaction mixture comprising the chlorinated alkane andthe chlorinated alkene, and extracting chlorinated alkene from thereaction mixture, wherein the concentration of the chlorinated alkene inthe reaction mixture present in the dehydrochlorination zone iscontrolled such that the molar ratio of chlorinated alkene:chlorinatedalkane is from 1:99 to 50:50.
 2. The process of claim 1, wherein themolar ratio of chlorinated alkene:chlorinated alkane in the reactionmixture is from 5:95 to 50:50.
 3. The process of claim 1, wherein themolar ratio of chlorinated alkene:chlorinated alkane in the reactionmixture is from 5:95 to 30:70.
 4. The process of claim 1, wherein thechlorinated alkane contacted with the catalyst in thedehydrochlorination zone has a purity of about 98.5% or higher.
 5. Theprocess of claim 1, wherein the chlorinated alkene is extracted from thereaction mixture on a continuous basis.
 6. The process of claim 1,wherein extraction of the chlorinated alkene from the reaction mixtureis achieved by distillation.
 7. The process of claim 1, wherein thechlorinated alkene is condensed from a gaseous mixture comprising thechlorinated alkene generated in the dehydrochlorination zone.
 8. Theprocess of claim 7, wherein the distillation is performed indistillation apparatus in fluid communication with thedehydrochlorination zone.
 9. The process of claim 8, wherein thedistillation apparatus is coupled to the dehydrochlorination zone. 10.The process of claim 1 where liquid reaction mixture is extracted fromthe dehydrochlorination zone and subjected to distillation usingapparatus remote from the dehydrochlorination zone.
 11. The process ofclaim 6, wherein the distillate comprises gaseous hydrochloric acid asan impurity which is extracted therefrom.
 12. The process of claim 1,wherein the operating temperature in the dehydrochlorination zone isabout 70° C. to about 250° C.
 13. The process of claim 1, wherein theoperating temperature in the dehydrochlorination zone is about 120° C.to about 170° C.
 14. The process of claim 1, further comprisingcontacting a mixture comprising chlorinated alkene, catalyst andchlorinated alkane starting material with an aqueous medium in anaqueous treatment zone.
 15. A process for removing oxygenated impuritiesfrom a mixture comprising a chlorinated alkene, oxygenated impuritiesand optionally a catalyst and/or a chlorinated alkane, comprisingcontacting the mixture with an aqueous medium to form a biphasic mixtureand extracting the organic phase from that biphasic mixture.
 16. Theprocess of claim 15 wherein the mixture comprises the mixture extractedfrom the dehydrochlorination zone in the process of claim
 15. 17. Theprocess of claim 14, wherein the pH of the mixture in the aqueoustreatment zone, following the addition of acid, is about 4 or lower. 18.The process of claim 14, wherein the mixture is contacted with ahaloalkane extraction agent.
 19. The process according to claim 14,wherein a biphasic mixture is formed in the aqueous treatment zone andan organic phase comprising chlorinated alkane and chlorinated alkene isextracted from the biphasic mixture.
 20. The process according to claim19, wherein chlorinated alkene is extracted from the organic phase. 21.The process according to claim 1, wherein the catalyst comprisesmetallic iron, ferrous chloride and/or ferric chloride.
 22. The processaccording to claim 1, wherein the chlorinated alkene is1,1,3-trichloropropene.
 23. The process according to claim 1 wherein thechlorinated alkane is 1,1,1,3-tetrachloropropane.
 24. The process ofclaim 1, wherein all surfaces of the apparatus in which the process iscarried out with which any chlorinated alkene-containing mixture willcontact during use of that apparatus have an iron content of about 20%or less, about 10% or less or about 5% or less, and/or are formed fromnon-metallic materials, for example enamel, glass, impregnated graphite(e.g. impregnated with phenolic resin), silicium carbide and/or plasticsmaterials such as polytetrafluoroethylene, perfluoroalkoxy and/orpolyvinylidene fluoride.
 25. A chlorinated alkene composition obtainablefrom the process of claim
 1. 26. The composition of claim 25 whichcomprises: about 95% or more, about 97% or more, about 99% or more,about 99.2% or more about 99.5% or more or about 99.7% or more of thechlorinated alkene, less than about 50000 ppm, less than about 20000ppm, less than about 10000 ppm, less than about 5000 ppm, less thanabout 2000 ppm, less than about 1000 ppm, less than about 500 ppm, lessthan about 200 ppm, or less than about 100 ppm of chlorinated alkanestarting material, less than about 1000 ppm, less than about 500 ppm,less than about 200 ppm, or less than about 100 ppm of chlorinated C₅₋₆alkane impurities, less than about 1000 ppm, less than about 500 ppm,less than about 200 ppm, or less than about 100 ppm of chlorinatedalkene impurities (i.e. chlorinated alkenes other than the compound ofinterest), less than about 1000 ppm, less than about 500 ppm, less thanabout 250 ppm, or less than about 100 ppm of oxygenated organiccompounds, less than about 500 ppm, about 250 ppm or less, about 100 ppmor less or about 50 ppm or less of water, and/or less than about 500ppm, less than about 200 ppm, less than about 100 ppm, less than about50 ppm, less than about 20 ppm, less than about 10 ppm or less thanabout 5 ppm metal.
 27. A chlorinated alkene composition which comprises:about 95% or more, about 97% or more, about 99% or more, about 99.2% ormore about 99.5% or more or about 99.7% or more of the chlorinatedalkene, less than about 50000 ppm, less than about 20000 ppm, less thanabout 10000 ppm, less than about 5000 ppm, less than about 2000 ppm,less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, or less than about 100 ppm of chlorinated alkane starting material,less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, or less than about 100 ppm of chlorinated C₅₋₆ alkane impurities,less than about 1000 ppm, less than about 500 ppm, less than about 200ppm, or less than about 100 ppm of chlorinated alkene impurities (i.e.chlorinated alkenes other than the compound of interest) less than about1000 ppm, less than about 500 ppm, less than about 250 ppm, or less thanabout 100 ppm of oxygenated organic compounds, less than about 500 ppm,about 250 ppm or less, about 100 ppm or less or about 50 ppm or less ofwater, and/or less than about 500 ppm, less than about 200 ppm, lessthan about 100 ppm, less than about 50 ppm, less than about 20 ppm, lessthan about 10 ppm or less than about 5 ppm metal.
 28. The composition ofclaim 25, wherein the chlorinated alkene is 1,1,3-trichloropropene. 29.The composition of claim 28, comprising less than about 1000 ppm, lessthan about 500 ppm, less than about 200 ppm, or less than about 100 ppmof 3,3,3-trichloropropene.
 30. Use of the composition of claim 25 as afeedstock in the synthesis of a halogenated alkene or halogenatedalkane.
 31. The use of claim 30, wherein the halogenated alkene orhalogenated alkane is a fluorinated or chlorinated alkene or afluorinated or chlorinated alkane.
 32. Use of the composition of claim27 as a feedstock in the synthesis of a halogenated alkene orhalogenated alkane.
 33. The use of claim 32, wherein the halogenatedalkene or halogenated alkane is a fluorinated or chlorinated alkene or afluorinated or chlorinated alkane.
 34. The process of claim 1, whereinthe chlorinated alkene produced is 1,1,3-trichloropropene.
 35. Theprocess of claim 1, wherein the chlorinated alkene produced is1,1,2,3-tetrachloropropene.
 36. The process of claim 1, wherein thechlorinated alkene produced is 1,1,3,3-tetrachloropropene.
 37. The useof claim 33, wherein the chlorinated alkene produced is1,1,3-trichloropropene.
 38. The use of claim 33, wherein the chlorinatedalkene produced is 1,1,2,3-tetrachloropropene.
 39. The use of claim 33,wherein the chlorinated alkene produced is 1,1,3,3-tetrachloropropene.